I actually don't find it hard to believe that Malaclypse and FP21 generated that amount of cash in the time of their existence. I made An easy bill in about a single week by trading with those two bases - especially the silver deliveries the junkers made were like christmas for my little Firefly.
~100 mill per hour by delievering it to Planet Harris, only one (or no system - depending on where the silver was sold) to cross and you made ~5k earning per unit. Then you brought back some Mox or Ship Hull Panels from Leeds to be a nice guy and earn a bit on the way back as well.
So if I could make a bill there in a week, why shouldn't the bases have made 20 bill in their whole existence? Sorry, but it were just the best trade routes I ever discovered so far in disco. Also the traffic was high there, the bases were sometimes emptied only after a few hours they got stocked up. In my eyes those bases did what player bases are supposed to do: generating alternative trade routes, generating traffic for the sake of createing a player interaction hot spot. And they did well at that.
Just my impressions here though. I neither can or can't prove or disprove here anything by hard facts and/or evidence, just as noone else could in this thread so far.